In a present application of an automatic toll for highways, a wireless receiving and transmitting RFID tag is installed in a vehicle. When the vehicle drives through a highway automatic toll gate, another wireless transceiver or an RFID tag reader-writer assembled above the toll gate reads the RFID tag installed in the vehicle. As the surrounding material of the toll gate and the surrounding vehicle situation are complex, it always arises that the reader-writer of a lane reads an RFID tag of a vehicle in an adjacent lane or an RFID in a rear vehicle is read by the RFID tag reader-writer of the roll gate which is going to read the RFID tag in the front vehicle because of the reflection, thereby leading to a payment error. Furthermore, a sudden lane change and speeding behavior are also the major causes of traffic accidents.
The present technology whereby induction coils placed in read-write regions are collected to judge whether the read tag ID is the right tag of the vehicle on this lane. But in many cases where both lanes are occupied by the vehicles or the vehicle ahead is in the induction coil but the rear vehicle is read, therefore, this method is not highly accurate. The sensitivity and the transmitting power of the RFID tag are also carefully judged so the RFID tag can be read in a defined region. However, by this method, the sensitivity of a plurality of the RFID tags needed to be judged which leads to the cost of RFID tags to increase. In the meantime, because the surrounding situation of the roll gate is very complex, this also leads to a change of the read-write region.